<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title>字符串大小写转换</title>
	</head>
	<body>
		<p>www.jb51.ITCASE.CN</p>
	</body>
	<script>
		function toUpperCase(str){
			return str.toUpperCase();
		}
		function toLowerCase(str){
			return str.toLowerCase();
		}
		var str = document.getElementsByTagName('p')[0].innerHTML;
		alert(toUpperCase(str))
		
	</script>
</html>
